There are many instances where there is a need to introduce a small accurately measured amount of a liquid into a much larger volume of liquid. For example, swimming pools must be constantly treated with chlorine and pH adjusting materials in order to keep the water in the pool in proper condition. Other examples are found in the food, chemical, or pharmaceutical industry where catalysts, reactants, enzymes, modifiers, etc. must be added slowly and continuously to a larger composition. It is advantageous if such an additive can be introduced through a pump which can provide a positive pressure for injecting the additive under the surface of the larger volume of liquid. It also is advantageous if that pump can be readily adjusted to change the output rate.
A peristaltic pump is one which has several advantages in meeting the above requirements. A peristaltic pump contains a flexible tubular passage through which the pumped material passes. A plurality of spaced rollers are pressed against the tube and rolled toward the outlet end of the tube. This arrangement provides the positive pressure in expelling the liquid from the tube and it provides an accurate volume of liquid between successive rollers. Convenient means for making the output adjustable involves a variable cam drive which provides intermittent movement to the rollers. All of these features are found in my U.S. Pat. No. 3,756,752 and in the earlier patent to S. Kaufman, U.S. Pat. No. 2,975,719.
The improvement provided in my present invention is found in the facility in which the feed rate control component may be assembled or disassembled for repair or for replacement of parts. All too frequently it is not possible to repair a pump without special tools. This is a disadvantage when the pump is employed in a residential swimming pool, and the pool owner is not equipped with all the special tools and know-how to service the pump. Accordingly, it is an object of this invention to provide such an apparatus which can readily be assembled or disassembled without special tools. Still other objects will appear from the more detailed description which follows.